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authornormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-08-28 00:24:08 (GMT)
committernormal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2018-08-28 00:24:08 (GMT)
commit4d9c23772ff75b88aa397d913a0477f233d38541 (patch)
tree702448b9753e7345484fd4be4d937f77a15720d6 /thread_pthread.h
parentfcaf874585df8984a23fb89a81bff522cc0ea52e (diff)
thread_pthread.h: rename `gvl.acquired' to `gvl.owner' and document
`acquired' was an old boolean variable, but nowadays it is a rb_thread_t pointer; "gvl.owner" seems like a more appropriate name. And document the contended path including waitq, timer, and timer_err. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64581 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'thread_pthread.h')
-rw-r--r--thread_pthread.h18
1 files changed, 14 insertions, 4 deletions
diff --git a/thread_pthread.h b/thread_pthread.h
index c64018b..f2b7e59 100644
--- a/thread_pthread.h
+++ b/thread_pthread.h
@@ -47,11 +47,21 @@ typedef struct native_thread_data_struct {
typedef struct rb_global_vm_lock_struct {
/* fast path */
- const struct rb_thread_struct *acquired;
- rb_nativethread_lock_t lock;
+ const struct rb_thread_struct *owner;
+ rb_nativethread_lock_t lock; /* AKA vm->gvl.lock */
- /* slow path */
- struct list_head waitq;
+ /*
+ * slow path, protected by vm->gvl.lock
+ * - @waitq - FIFO queue of threads waiting for GVL
+ * - @timer - it handles timeslices for @owner. It is any one thread
+ * in @waitq, there is no @timer if @waitq is empty, but always
+ * a @timer if @waitq has entries
+ * - @timer_err tracks timeslice limit, the timeslice only resets
+ * when pthread_cond_timedwait returns ETIMEDOUT, so frequent
+ * switching between contended/uncontended GVL won't reset the
+ * timer.
+ */
+ struct list_head waitq; /* <=> native_thread_data_t.node.ubf */
const struct rb_thread_struct *timer;
int timer_err;